The C49 to C54-TiSi2 transformation in self-aligned silicide applications

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Abstract
We show that when processing conditions closely mimic those used in the conventional self‐aligned silicide process, the effective activation energy for the polymorphic phase transformation of orthorhombic base‐centered (oC12) C49‐TiSi2 to the low‐resistivity orthorhombic face‐centered (oF24) C54‐TiSi2 phase is over 1 eV higher than previously reported literature values where a 1‐step heat cycle was used. For C49‐TiSi2 films formed at temperatures of 600 and 625 °C on (100) single crystal silicon substrates, the activation energy was determined to be 5.6±0.3 and 5.7±0.13 eV, respectively, for the transformation of this phase into C54‐TiSi2 in the temperature range of 625–700 °C. The higher activation energy obtained with the simulation of the self‐aligned silicide processing conditions suggests that the conventional processing may need to be modified for future semiconductor applications.